Tumpisa (Death Valley), a desert valley in a large basin and range formation in Eastern California, has been a lake many times in the past. The rock of the eastern mountain ranges were formed from sediment accumulation and volcanic eruptions at the bottom of the ancient lake between 200 to 50 million years ago. The lake has now been dry for over 10,000 years. The canyons in the mountains are still carved out by intensive flooding from rains. In many ways, this desert was formed by water and is still honed by it.